Communication apparatus and communication system having automatic attribution switching

A communication system comprising:

• an integrated services digital network (ISDN) having a plurality of channels;
• first and second terminals connected to a first subscriber's line of said ISDN, attribution of said second terminal;
• and
• third and fourth terminals connected to a second subscriber's line of said ISDN, attribution of said third terminal being different from attribution of said fourth terminal,
• wherein said first terminal informs said ISDN that attribution is switched from said first terminal to said second terminal in a case where said first and third terminals are connected to use one channel of said ISDN,
• said ISDN calls said second and fourth terminals on the basis of the information of switching the attribution, and
• said second terminal called by said ISDN automatically transmits the data to said fourth terminal by using the channel which had been used by said first and third terminals.

A communication system comprising:

• a first station wherein first and second terminals are connected on a first subscriber's line;
• a second station wherein third and fourth terminals are connected on a second subscriber's line;
• and
• an integrated services digital network (ISDN) having a plurality of channels for connecting said first station to said second station,
• wherein said first terminal comprises:
• communication means for performing a communication to said third terminal in said second station through one channel of said ISDN;
• switch means for switching a communication service for said second terminal so as to use said one channel for communication between said second and fourth terminals;
• detection means for detecting that the communication service has been returned after the communication between said second and fourth terminals is completed, in response to a call from said ISDN;
• selection means for selecting one of connection and disconnection of the channel to said second station when the communication service has been returned;
• and
• disconnection means for disconnecting the channel when said detection means detects that the communication service has been returned in response to disconnection of the channel being selected by said selection means.

A communication system comprising:

• a first station wherein first and second terminals are connected on a first subscriber's line;
• a second station wherein third and fourth terminals are connected on a second subscriber'lines;
• and
• an integrated services digital network (ISDN) having a plurality of channels for connecting said first station to said second station,
• wherein said first terminal comprises:
• communication means for performing a communication to said third terminal in said second station through one channel of said ISDN;
• switch means for switching a communication service of said ISDN to said second terminal so as to use said channel for communication between said second and fourth terminals;
• display means for displaying that the communication service has been switched to said second terminal by said switch means;
• and detection means for detecting that the communication service has been returned from said second terminal after the switching of the communication service to said second terminal by said switch means is completed,
• wherein said display means continues the display until said detection means detects that the communication service has been returned.

A communication system comprising:

• an integrated services digital network (ISDN) having a plurality of channels;
• first and second terminals connected to a first subscriber's line of said ISDN, attribution of said first terminal being different from attribution of said second terminal;
• and
• third and fourth terminals connected to a second subscriber's line of said ISDN, attribution of said third terminal being different from attribution of said fourth terminal;
• wherein said first terminal informs said ISDN that attribution is switched from said first terminal to said second terminal in a case where said first and third terminals are connected to use one channel of said ISDN,
• said ISDN calls said second and fourth terminals on the basis of the information of switching the attribution,
• said second terminal called by said ISDN automatically transmits data to said fourth terminal by using the channel which had been used by said first and third terminals, and
• said first terminal informs that said second terminal is in communication to said fourth terminal.